De novo Mutation Enables NOTCH3ECD Aggregation and Mitochondrial Dysfunction via Interactions with BAX and BCL-2.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) caused by NOTCH3 mutations is the most common monogenic hereditary pattern of cerebral small vessel disease. The aggregation of the mutant NOTCH3 may play a cytotoxic role in CADASIL. However, the main mechanism of this process remains unclear. OBJECTIVE: We aimed to investigate the possible pathogenesis of the mutant NOTCH3 in CADASIL. METHODS: The clinical information of two pedigrees were collected and analyzed. Furthermore, we constructed cell lines corresponding to this mutation in vitro. The degradation of the extracellular domain of NOTCH3 (NOTCH3ECD) was analyzed by Cycloheximide Pulse-Chase Experiment. Flow cytometry and cell counting kit-8 assay were performed to observe the effects of the NOTCH3 mutation on mitochondrial function and apoptosis. RESULTS: We confirmed a de novo heterozygous missense NOTCH3 mutation (c.1690G > A, p. A564T) in two pedigrees. In vitro, the NOTCH3ECD aggregation of A564T mutant may be related to their more difficult to degrade. The mitochondrial membrane potential was attenuated, and cell viability was significant decreased in NOTCH3ECD A564T group. Interestingly, BAX and cytochrome c were significantly increased, which are closely related to the mitochondrial-mediated pathway to apoptosis. CONCLUSION: In our study, the aggregation of NOTCH3ECD A564T mutation may be associated with more difficult degradation of the mutant, and the aggregation may produce toxic effects to induce apoptosis through the mitochondrial-mediated pathway. Therefore, we speculated that mitochondrial dysfunction may hopefully become a new breakthrough point to explain the pathogenesis of cysteine-sparing NOTCH3 mutations.

Decreased mitochondrial D-loop region methylation mediates an increase in mitochondrial DNA copy number in CADASIL.

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a typical neurodegenerative disease associated with mitochondrial dysfunction. Methylation of the D-loop region and mitochondrial DNA copy number (mtDNAcn) play a critical role in the maintenance of mitochondrial function. However, the association between D-loop region methylation, mtDNAcn and CADASIL remains unclear. METHODS: Overall, 162 individuals were recruited, including 66 CADASIL patients and 96 age- and sex-matched controls. After extracting genomic DNA from the peripheral white blood cells, levels of D-loop methylation and mtDNAcn were assessed using MethylTarget sequencing and real-time PCR, respectively. RESULTS: We observed increased mtDNAcn and decreased D-loop methylation levels in CADASIL patients compared to the control group, regardless of gender stratification. Besides, we found a negative correlation between D-loop methylation levels and mtDNAcn. Mediation effect analysis shows that the proportion of the association between mtDNAcn and CADASIL that is mediated by D-loop methylation is 11.6% (95% CI 5.6, 22.6). After gender stratification, the proportions of such associations that are mediated by D-loop methylation in males and females were 7.2% (95% CI 2.4, 19.8) and 22.0% (95% CI 7.4, 50.1), respectively. CONCLUSION: Decreased methylation of the D-loop region mediates increased mtDNAcn in CADASIL, which may be caused by a compensatory mechanism of mitochondrial dysfunction in patients with CADASIL.

The efficiency of carbon trading market in China: evidence from variance ratio tests.

On December 19, 2017, China's National Development and Reform Commission (NDRC) announced the official launch of the much-anticipated national emissions trading system (ETS), which is a critical period for the transition from the eight carbon emission trading pilot projects to the national market at this stage. Comprehensively evaluating the efficiency of China's eight carbon trading pilots is vital for strengthening the construction of its national ETS. This paper investigates the weak-form efficiency of eight carbon trading markets in China. We use a series of variance ratio tests to identify the efficiency from the market set up to the May 4, 2018, of all markets. The results indicate that the majority of the carbon trading markets are inefficient and only Beijing, Hubei, and Fujian markets are efficient. The China's carbon trading market is gradually maturing and implemented. In addition, we analyze the factors have impact on the market efficiency. It shows that the liquidity, volume, allocation allowance, and transparency in information are significant factors; meanwhile, the regional policy and cross cooperation also are important factors. Finally, this paper puts forward several policy recommendations on how to strengthen the effectiveness of China carbon trading markets based on the empirical results.